Integration of component devices of a consumer electronics product is desirable to reduce form factor. Integration often results in size reduction because multiple devices become parts of one integrated system. The integrated system itself can then be progressively reduced in size over time. Integration of multiple devices into one system is complex and made more complex in cases where each device is of a different type and has different manufacturing requirements.
For example, acoustic sensors (e.g. microphones) are utilized in applications with environmental sensors (e.g. humidity and/or temperature sensors). Presently, the humidity and/or temperature sensors, while being a part of the same product as the microphone, are packaged separately from the microphone. Stated differently, the types of sensors are located as discrete components within the same product. This leads to increased real estate cost in addition to complexity of manufacturing, as each component must be assembled separately on to the host circuit board of the product. A single package comprising a plurality of sensors would significantly simplify manufacturing, reduce costs, and reduce overall board area. Furthermore if the sensors can be integrated along with an application specific integrated circuit (ASIC) in the same package, further cost and size reductions can be realized.
However, efforts to integrate the foregoing sensors are hindered by several challenges. One such challenge is in bonding the microphone, a part of the acoustic sensor, to an application specific integrated circuit (ASIC). Temperatures used for such bonding are typically and approximately 430 degrees Celsius and higher. Environmental sensing materials, such as polymers, are not likely to survive at such temperatures. Another challenge occurs during release etching, a process utilized during manufacturing of the acoustic sensor, when the polymer experiences adverse effects rendering it defective in most if not all cases. Such shortcomings have prevented the integration of acoustic sensors with environmental sensors on the same IC substrate and/or package substrate.
It would be desirable to have an integrated package and methodology for making an integrated package that contains both acoustic and environmental sensors and also an ASIC for processing data generated by these sensors.